src/cpu/x86/smm/smihandler.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * Copyright (C) 2008-2009 coresystems GmbH
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; version 2 of
   9  * the License.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  19  * MA 02110-1301 USA
  20  */
  21
  22 #include <arch/io.h>
  23 #include <arch/romcc_io.h>
  24 #include <console/console.h>
  25 #include <cpu/x86/cache.h>
  26 #include <cpu/x86/smm.h>
  27
  28 typedef enum { SMI_LOCKED, SMI_UNLOCKED } smi_semaphore;
  29
  30 /* SMI multiprocessing semaphore */
  31 static volatile smi_semaphore smi_handler_status = SMI_UNLOCKED;
  32
  33 static int smi_obtain_lock(void)
  34 {
  35         u8 ret = SMI_LOCKED;
  36
  37         asm volatile (
  38                 "movb %2, %%al\n"
  39                 "xchgb %%al, %1\n"
  40                 "movb %%al, %0\n"
  41                 : "=g" (ret), "=m" (smi_handler_status)
  42                 : "g" (SMI_LOCKED)
  43                 : "eax"
  44         );
  45
  46         return (ret == SMI_UNLOCKED);
  47 }
  48
  49 static void smi_release_lock(void)
  50 {
  51         asm volatile (
  52                 "movb %1, %%al\n"
  53                 "xchgb %%al, %0\n"
  54                 : "=m" (smi_handler_status)
  55                 : "g" (SMI_UNLOCKED)
  56                 : "eax"
  57         );
  58 }
  59
  60 #define LAPIC_ID 0xfee00020
  61 static inline __attribute__((always_inline)) unsigned long nodeid(void)
  62 {
  63         return (*((volatile unsigned long *)(LAPIC_ID)) >> 24);
  64 }
  65
  66 void io_trap_handler(int smif)
  67 {
  68         /* If a handler function handled a given IO trap, it
  69          * shall return a non-zero value
  70          */
  71         printk_debug("SMI function trap 0x%x: ", smif);
  72
  73         if (southbridge_io_trap_handler(smif))
  74                 return;
  75
  76         if (mainboard_io_trap_handler(smif))
  77                 return;
  78
  79         printk_debug("Unknown function\n");
  80 }
  81
  82 /**
  83  * @brief Set the EOS bit
  84  */
  85 static void smi_set_eos(void)
  86 {
  87         southbridge_smi_set_eos();
  88 }
  89
  90 /**
  91  * @brief Interrupt handler for SMI#
  92  *
  93  * @param smm_revision revision of the smm state save map
  94  */
  95
  96 void smi_handler(u32 smm_revision)
  97 {
  98         unsigned int node;
  99         smm_state_save_area_t state_save;
 100
 101         /* Are we ok to execute the handler? */
 102         if (!smi_obtain_lock()) {
 103                 /* For security reasons we don't release the other CPUs
 104                  * until the CPU with the lock is actually done
 105                  */
 106                 while (smi_handler_status == SMI_LOCKED) /* wait */ ;
 107                 return;
 108         }
 109
 110         node=nodeid();
 111
 112         console_init();
 113
 114         printk_spew("\nSMI# #%d\n", node);
 115
 116         switch (smm_revision) {
 117         case 0x00030002:
 118         case 0x00030007:
 119                 state_save.type = LEGACY;
 120                 state_save.legacy_state_save = (legacy_smm_state_save_area_t *)
 121                         (0xa8000 + 0x7e00 - (node * 0x400));
 122                 break;
 123         case 0x00030100:
 124                 state_save.type = EM64T;
 125                 state_save.em64t_state_save = (em64t_smm_state_save_area_t *)
 126                         (0xa8000 + 0x7d00 - (node * 0x400));
 127                 break;
 128         case 0x00030064:
 129                 state_save.type = AMD64;
 130                 state_save.amd64_state_save = (amd64_smm_state_save_area_t *)
 131                         (0xa8000 + 0x7e00 - (node * 0x400));
 132                 break;
 133         default:
 134                 printk_debug("smm_revision: 0x%08x\n", smm_revision);
 135                 printk_debug("SMI# not supported on your CPU\n");
 136                 /* Don't release lock, so no further SMI will happen,
 137                  * if we don't handle it anyways.
 138                  */
 139                 return;
 140         }
 141
 142         /* Call chipset specific SMI handlers. */
 143         if (cpu_smi_handler)
 144                 cpu_smi_handler(node, &state_save);
 145         if (northbridge_smi_handler)
 146                 northbridge_smi_handler(node, &state_save);
 147         if (southbridge_smi_handler)
 148                 southbridge_smi_handler(node, &state_save);
 149
 150         smi_release_lock();
 151
 152         /* De-assert SMI# signal to allow another SMI */
 153         smi_set_eos();
 154 }